Steven D'Aprano <steve+pyt...@pearwood.info> added the comment:
This is a floating point issue, not a bug. Floats inherently only have a limited precision available, so they are not always the exact number you think they are. Using 1e9 forces the result to be a float, which introduces rounding errors into the calculation. If you use an exact integer, the calculation is exact: py> 151476660579404160000-151476660579404160000//1000000007 * (10**9+7) 67543367 py> 151476660579404160000 % (10**9+7) 67543367 *This is not a Python bug* this is an inherent limitation of floating point numbers and the same issues will occur in any language that uses floats. https://docs.python.org/3/faq/design.html#why-am-i-getting-strange-results-with-simple-arithmetic-operations ---------- nosy: +steven.daprano resolution: -> not a bug stage: -> resolved status: open -> closed _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue39738> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
